/**
 * Copyright (c) <2010>, <SUNNY GUPTA>
 * All rights reserved.

 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   * Neither the name of the <ORGANIZATION> nor the
 *     names of its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL <SUNNY GUPTA> BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.gwtp.investmentadvisor.server.core.cacheservice.impl;

import com.google.appengine.api.memcache.Expiration;
import com.google.appengine.api.memcache.MemcacheService;
import com.google.appengine.api.memcache.MemcacheServiceFactory;
import com.google.appengine.api.memcache.MemcacheService.SetPolicy;
import com.gwtp.investmentadvisor.server.core.cacheservice.CacheService;

/**
 * Inplementation for {@link CacheService}.
 * @author Sunny Gupta
 *
 */
public class CacheServiceImpl implements CacheService {
  private static final String NULL_KEY_ERROR_MESSAGE = "The cache doesn't allow storing null keys";

  private MemcacheService cache;

  public CacheServiceImpl() {
    // Initialize memcacheservice
    cache = MemcacheServiceFactory.getMemcacheService();
  }

  /* (non-Javadoc)
   * @see com.gwtp.investmentadvisor.server.core.cacheservices.CacheService#contains(java.lang.Object)
   */
  @Override
  public boolean contains(Object key) {
    // Doesn't support null keys
    if (key == null) {
      return false;
    } else {
      return cache.contains(key);
    }
  }
  
  /* (non-Javadoc)
   * @see com.gwtp.investmentadvisor.server.core.cacheservices.CacheService#get(java.lang.Object)
   */
  @Override
  public Object get(Object key) {
    // Check for null key
    if (key == null) {
      // Return null
      return null;
    }
    // First get Object
    Object obj = cache.get(key);
    if (cache.contains(key)) {
      return obj;
    } else {
      return null;
    }
  }
  
  /* (non-Javadoc)
   * @see com.gwtp.investmentadvisor.server.core.cacheservices.CacheService#put(java.lang.Object, java.lang.Object)
   */
  @Override
  public void put(Object key, Object value) {
    this.put(key, value, null, null);
  }
  
  /* (non-Javadoc)
   * @see com.gwtp.investmentadvisor.server.core.cacheservices.CacheService#put(java.lang.Object, java.lang.Object, int)
   */
  @Override
  public void put(Object key, Object value, int relativeExpirationTimeInSeconds) {
    this.put(key, value, Expiration.byDeltaSeconds(relativeExpirationTimeInSeconds), null);
  }
  
  /* (non-Javadoc)
   * @see com.gwtp.investmentadvisor.server.core.cacheservices.CacheService#put(java.lang.Object, java.lang.Object, com.google.appengine.api.memcache.Expiration, com.google.appengine.api.memcache.MemcacheService.SetPolicy)
   */
  @Override
  public void put(Object key, Object value, Expiration expires, SetPolicy policy) {
    // Check for null key
    if (key == null) {
      // Do not store
      throw new IllegalArgumentException(NULL_KEY_ERROR_MESSAGE);
    }
    
    // Check for null policy
    if (policy == null) {
      cache.put(key, value, expires, SetPolicy.SET_ALWAYS);
    } else {
      cache.put(key, value, expires, policy);
    }
  }
  
  /* (non-Javadoc)
   * @see com.gwtp.investmentadvisor.server.core.cacheservices.CacheService#getMemcacheService()
   */
  @Override
  public MemcacheService getMemcacheService() {
    return cache;
  }
}
